title: Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization: applications in pressure-sensitive adhesives.
abstract: Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.
authors.affiliation: Institute for Polymer Materials (POLYMAT) and Grupo de Ingeniería Química, Departamento de Química Aplicada, University of the Basque Country, Joxe Mari Korta Zentroa, Tolosa Etorbidea 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Aitziber
authors.initials: A
authors.lastname: Lopez
authors.forename: Elise
authors.initials: E
authors.lastname: Degrandi-Contraires
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Canetta
authors.forename: Costantino
authors.initials: C
authors.lastname: Creton
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Keddie
authors.forename: José M
authors.initials: JM
authors.lastname: Asua